Spotlight Feature Articles MINE SAFETY - Page 4

“ Depending on the specific situation and the extent of the emergency , the rescue services must immediately switch on their own breathing equipment after descending into the shaft and walking to the emergency site ,” PAUS says . “ In doing so , they consume part of the volume of the breathing mixture ( compressed oxygen ) contained in the breathing equipment .
“ As a result , the longer they travel to the emergency scene with their breathing equipment switched on , the less breathing mixture – and , thus , working time reserves – remains for solving the main tasks : for clarifying the location and possible causes of the emergency , for searching for injured persons , and for bringing the victims from the danger zone to the exits of the mine for evacuation .”
The cooperation of specialists from Dräger , Goldcorp ( now Newmont ) and PAUS is changing this with the MRV 9000 Mine Rescue Vehicle , which has been developed to deliver the rescue units safely , reliably and as close as possible to the emergency site .
The high operational reliability of the MRV 9000 in underground mines is ensured by the robust construction of the basic vehicle ( from PAUS ’ MinCa 18A series ) and the life support system of Dräger , the companies say .
In its standard version , the MRV 9000 mine rescue vehicle is fitted with a Deutz TCD 2012 Stage 3a diesel engine with 95 kW of power , water cooling and exhaust gas turbocharging . Able to consume various fuel qualities , the MRV 9000 ’ s exhaust gases are cleaned with a powerful filter .
The engine ’ s control system is able to reduce machine downtime , according to PAUS . For example , in a situation where low lube oil pressure or overheating of the coolant is detected , the engine ’ s power will , first , reduce and then , second , completely stop to protect the unit . The real-time engine status is displayed on a large dashboard display close to the driver .
The MRV 9000 is equipped with a customisable fire extinguishing system .
In each of its designs , if the engine compartment catches fire , the engine automatically stops
The MRV 9000 Mine Rescue Vehicle has been developed to deliver rescue units safely , reliably and as close as possible to the emergency site
operating and the extinguishing medium , such as foam , water spray , or powder , is automatically or manually injected into the engine compartment . Hand-held fire extinguishers with around 10 kg of extinguishing medium are within easy reach , according to PAUS .
The hydrostatic four-wheel drive of the MRV 9000 provides high tractive power via planetary gears and the suspension provides excellent road grip when driving on rough and bumpy roads , PAUS says . Optimum handling and fuel consumption are maintained at speeds of up to 35 km / h , it added .
The design of the independent suspension of the Dana Spicer Clark 212 front axle ( steering axle ) and Dana Spicer Clark 112 rear axle is identical . It consists of two springs and two shock absorbers each , two steering rods and two triangular bars each , with a tie rod lever attached to the vehicle frame . The maximum load capacity of an axle is 8 t , which ensures excellent stability of the vehicle frame , while the MRV 9000 has a total permissible weight of 11 t . The wheels are fitted with off-road tyres of 9.00-R20 size .
The two-door driver ’ s cab with an additional seat is separated from the rescue cassette . The rescue cassette has six seats , a left-hand access door and an additional rear door . All eight seats , equipped with safety belts , are dimensioned so mine rescuers equipped with a tool kit and breathing equipment on their back – eg Dräger PSS BG4 Plus – can sit comfortably . The driver ’ s cab and the cassette of the MRV 9000 are pressurised and equipped with built-in safety systems in compliance with ROPS and FOPS standards . In addition , a hatch is installed in the middle of the body roof as an additional emergency exit .
The steering system of the vehicle is equipped with a Danfoss steering booster . In the case of a malfunction , the vehicle can still be steered using an emergency mechanism .
The brake system of the MRV 9000 is a hydraulic dual-circuit system . By pressing the brake pedal , all multi-disc oil brakes on the wheels are activated . The hydrostatic drive is , at the same time , an additional working brake for the vehicle – when the driver takes their foot off the accelerator , the vehicle automatically brakes . This is especially effective when driving downhill .
The vehicle ’ s electrical system works with direct current and a voltage of 24 V , supplied by two 12 V batteries with a capacity of 110 Ah each and an A / C generator ( 80 A ) with a voltage of 28 V .
Built with a width of 2.2 m , height of 2.64 m , length of 6.15 m , a wheelbase of 3.26 m and ground clearance of 260 mm , the MRV 9000 has turning radii of 3.7 m ( inner ) and 7 m ( outer ).
The vehicle is equipped with an integrated life support system to allow mine rescuers to safely reach the emergency site and evacuate injured personnel . Filtered air is injected into the driver ’ s cab and rescue cassette for breathing during the entire journey .
“ The technological basis and structure of the filling system , developed and installed by the specialists of the Dräger company , includes the following elements : compartments for storage of the cylinders with the oxygen-air mixture for breathing ; panels for controlling the supply of the air mixture ; safety valves that drain the air from the driver ’ s cab and the cassette and prevent the ingress of contaminated mine air ; gas detectors that control the condition of the air and signal the exceedance of the permissible limits of the concentration of hazardous gases in the driver ’ s cab and the cassette .”
The life support system can operate in two modes : cleaning the air and feeding the air mixture into the cassette and into the driver ’ s cab ; and flushing the cassette and the driver ’ s cab to displace contaminated air .
In the cleaning mode , used during much of the rescue operation , the air mixture from the cylinders is continuously fed through pipes into the operator ’ s cab and the cassette via flow regulators . These regulate the amount of air supply , which depends on the number of rescuers in the cab and cassette . In keeping with industry
International Mining | OCTOBER 2020